In recent years, digital computer uses have been limited because of an exponential increase in the cost of fine processing technology. As a result, analog computers have been given attention. A weighted summing circuit in an analog computer is formed by capacitive coupling; that is, connecting a plurality of capacitances in parallel to realize a multiplication circuit. However, such a construction leads to low accuracy for generated bias voltage caused by an unfitted threshold value where a closed loop inverter is used to compensate the accuracy of output.